I read somewhere never to put wood ash on Tomatos because they are acid loving and ash is very alkaline. I also read never to combine wood ash with ammonia, nitrogen or urea-based fertilizers, as they react and the nitrogen/ammonia is released or something.
BUT, then I read this:
"A team of Finnish researchers found that sprinkling tomatoes with human urine mixed with wood ash was the ultimate eco-friendly fertiliser. The mixture produced bumper harvests when compared to untreated plants. ...crops up to four times larger.
It worked just as well with cucumber, corn, cabbage and other crops. Although scientists have previously tested urine on plants, this is the first one to mix it with wood ash."
Um, has anyone tried this?